I have a 1974 914 2 liter with a single weber carb. I aquired it a couple of months ago. 2 weeks ago I did a tune up--plugs, rotor, cap, points, condenser and new ignition wires. It ran like a porsche should when I finished. Timing is at 34 degrees BTDC at 3200 rpm

I live in Chicago and a week ago it got really hot--mid nineties and humid. Since it's been hot the car runs rough and seems to really lack power--especially when acelerating fast under a load or from a stop.

Any suggestions? It seems to be related to it being so hot--I can't find anything else different.

You might check the distributor cap and plug wires to see if there is moisture inside the cap or inside the boots that is making a misfire. Try running the car at night with no lights around to see if there is any arching or voltage leaks. Good luck

After about five single carbs, I finally went with dual webbers. Best choice I ever made. The heat always seemed to affect my carbration performance. Floats always stuck and idle always fluctuated. It is hot most of the year where I live. It was always a constant adjustment hassle. I Have had virtually no problems with the duals, and seems like my adjustments stay where I put them!

Also try running Premium gasoline. That seemed to make the single carb run smoother for a while, and also helped to burn the moisture from the humidity. Ok, not acutally sure on that....sounded good though.